Electro-magnetic motor



W. W. GRISOOM Electro-Magnetic Motor No. 227,623. Patented May18, I880.

N-PEYERS. FHOTO-LITMOGRAPHER, WASHINGTON D C UNITED STATES PATENTOFFICE.

WILLIAM W. GRISOOM, OF PHILADELPHIA, PENNSYLVANIA.

ELECTRO-MAGNETIC MOTOR.

SPECIFICATION forming part of Letters Patent No 227,623, dated May 18,1880.

Application filed October .21, 1879.

To all whom it may concern:

Be it known that I, VVILLIAM W. GRIscoM, of Philadelphia, Pennsylvania,have invented new and useful Im1t)rovementsinEleetro-Magnetic'Motors, ofwhich thefollowingis a specification.

This invention relates to certain improvements in the construction ofelectromagnetic motors or dynamo-electric machines, the b jects of theinvention being to improve the construction of the cylindrical armatureand to construct the bearings of the pulley so that the belt may bearranged at any angle.

The invention also relates to other improvements in the motor and itsmeans of support, as more fully described hereinafter, reference beingbad to the accompanying drawings, in which- Figure 1 is a perspectiveview of the motor; Fig. 2, an end View; Fig. 3, a longitudinal section;Fig. 4, a sectional view of the improved armature Fig. 5, a perspectiveview of the brushes, and Fig. 6 a view showing a method of suspendingthe motor.

The general construction of the motor is similar to that shown anddescribed in an application for Letters Patent filed by me on the samedate as this, there being a rotary armature,A, commutator a, andcommutatorbrnshes I), combined with electro magnets 13 B. Theconstruction and arrangement of the magnets and connections, however,form no part of the present application.

Instead of forming the armature of a bar of iron with two oppositerectangular grooves, as in the ordinary Siemens armature, the bar hastwo V-shaped grooves cut in it, so as to form a bar Z-shaped in section,as shown in Fig. 4, wire being wrapped in these grooves, as usual. Insome cases the wire wrapping may be dispensed with. The object of makingthe bar of this shape is to provide a graduallyincreasing attraction onthe part of the armature for the magnet when the machine is inoperation.

The rib which connects the poles of the armature may, if desired, bemade of one or more separate plates, round which the wires maybewrapped.

In order to secure the wires in place and prevent them from flying outby the centrifugal force, the bundle of wires is covered with cement,preferably consisting of asbestns and silicate of soda, so as to resistany heat which may be generated in the coils. The wires of the magnetsare also preferably covered with similar cement.

On the end of the shaft of the armature is secured a groovedcone-pulley, I, instead of the usual single-grooved pulley, the outerend of the shaft being supported in a bracket, p, which is secured tothe frame M by a screw. A number of threaded openings are provided inthe frame, so that the bracket may be adjusted to different positions,as indicated by dotted lines, according to the position of the belt, inorder to allow the latter to be readily slipped on or off the pulley.

The object of employing a cone-pulley is to permitthe motor to bemaintained at that nor mal speed which is found to give the bestresults, no matter what may be the actual load on the motor.

I have found by experiment that when the load becomes too great for aneleetro-nmgnetie motor with an ordinary single pulley the speed and workactually done decrease in a ratio, vastly greater than the increase ofthe load. There, in the case of an ordinary motor, such as asteam-engine, doubling the load would only decrease the speed one-half,in the ease of an electric motor the speed would be diminished in a muchgreater ratio. For instance, where, with a one-size pulley, the electricmotor is capable of lifting ten pounds eighty feet per minute, eightypounds would not be lifted ten feet per minute, but would stop the motorentirely, and forty pounds, instead of being raised at the rate oftwenty feet per minute, would only be raised at the rate of five feetperminute. In such a case, by employing a cone-pulley the speed of rotationof the motor may be brought up to its normal standard by removing thebelt toward the smaller end of the pulley, and the somewhat curiousresult is attained of increasing the speed of the driven pulley by thusdecreasing the size or leverage of the driving-pulley.

Instead of a cone-pulley, gear-wheels or an adjustable crank may beemployed for the same purpose.

The wire brushes 7) b of the commutator are electrically connected tothe holder 0 by slotting the latter, Fig. 5, then insertingthe brushesin the slot, and finally forcin the jaws together so as to gripe thebrushes, this method being safer than the usual method of fastening thebrushes by solder, which injures the electrical contact, or a screw,which will at times jar loose or cut the wires.

The above-described motor, bein comparativel y light and compact, isespecially adapted for driving denial tools and similar devices, and forthis purpose it is suspended, by means of an adjustable arm, wire,chain, or cord, from the ceiling or a suitable bracket, so that themotor is free to be moved about, and its driving-shaft moved in anydirection to accommodate itself to the movements given to the tool, thelatter being driven from the motel-through the medium of flexibleshat'ting X, Fig. 3, secured to a shaft, Y, in a bracket on themotorframe, and having a eoue-pulley corresponding with the pulley onthe shaft of the armature; or, if desired, the flexible shat'ting may beconnected directly to the end of the armature-shaft. I11 some cases itmay be desirable to connect the tool directly to the shaft of the motorwithout the use of flexible shal'ting, in which case the motorshould bebalanced.

In Fig. 6 lhave shown the motor as suspended from the ceiling byajointed arm, F, having a balland-socket or other universal joint, f, sothat the lower portion of the arm carrying the motor may be adjusted tovarious positions, and secured, if desired, by a setscrew.

I am aware that it has been proposed to support electric pens by meansot'ayielding spring; but for motors of the character shown in thepresent case it is important to support them by inelastic, though insome cases flexible, suspension devices, so that the support may notyield in a downward direction.

I claim as my invention 1. In an electromagnetic motor or dynamoelectricmachine, the combination of magnets with arotary armature whose bar orbars are Z-shaped in section, as and for the purpose described.

2. The combination of the motorl'rame and the rotary armature having apulley and belt with the adjustable bracket.

The combination of wire commutatorbrushes with a slotted metallicholder, electric contact between the brushes and holder being secured byforcing the jaws of the latter together over the wires of the brushwithout screw or solder, as set forth.

4-. The combination of the motor with inelastic devices, substantiallyas described, for suspending the same, whereby the said motor maybemoved in any desired direction, but without yielding in a downwarddirection.

5. The combination of the wire covering of an armature or magnet with acement capable of resisting heat, as set forth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

Will. W GRISUOM. lVitnesses:

ALEXANDER PAT'rnusoN, HARRY SMITH.

